JP2005064948A - Antenna matching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly solve the impedance mismatch of an antenna mounted in a portable telephone etc. caused by an approach to a human body to thereby reduce a power loss caused by the impedance mismatch. <P>SOLUTION: Impedance adjusting variable capacitors VC1, VC2 are connected to a transmitting antenna element TA1, and variable capacitors VC3, VC4 are connected to a receiving antenna element RA1. The capacitance value of each variable capacitor brought into an impedance-matched state is previously prepared on a table so as to correspond to the distance between the antenna element and the human body and stored in a memory 106. After finishing an adaptive control process of either the transmitting antenna element TA1 or the receiving antenna element RA1, other capacitance values corresponding to the capacitance value at this time are read out of the table, and the adaptive control process is executed about other antenna elements with the read values taken as initial values. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an antenna matching device, and is suitable for application to a wireless communication device such as a mobile phone.

  FIG. 9 is a diagram showing a configuration of a conventional mobile phone. In this figure, the housing 11 includes a helical antenna 12 outside the housing, and the helical antenna 12 and a matching circuit 13 inside the housing are connected.

  Further, the matching circuit 13 is connected to the wireless transmission unit 15 and the wireless reception unit 16 via the changeover switch 14 inside the housing. The matching circuit 13 is normally determined so that the input impedance of the helical antenna 12 is in a matching state at the operating frequency in free space.

FIG. 10 is a diagram illustrating an example of the cellular phone illustrated in FIG. 9 when close to the human body. Here, a call state is shown when the human body is close. In this state, the input impedance of the helical antenna 12 changes greatly, impedance mismatch occurs, and power loss increases. In order to suppress this power loss, an apparatus and algorithm for automatically matching the input impedance of the helical antenna 12 have already been invented (see Patent Document 1).
JP-A-8-097733

  However, since there is only one helical antenna device and the frequency band of the helical antenna device is narrow, the convergence time by control is delayed when the transmission frequency and the reception frequency are separated. Further, when the transmission frequency and the reception frequency are separated and transmission and reception are performed simultaneously, there is a problem that mismatch occurs in either transmission or reception, and the call quality is greatly deteriorated.

  The present invention has been made in view of the above points, and an antenna device mounted on a mobile phone or the like eliminates impedance mismatch occurring in the vicinity of a human body in a short time, and reduces power loss due to impedance mismatch. An object of the present invention is to provide an antenna matching device.

  In order to solve such a problem, an antenna matching apparatus of the present invention includes a plurality of antenna elements, matching means connected to the antenna elements and adjusting impedance, and signals reflected when power is supplied to the antenna elements. First detection means for detecting any one of reflection coefficient and voltage standing wave ratio, second detection means for detecting a signal received by the antenna element, and control information of the matching means for human body and antenna element And a control means for adaptively controlling the matching means so as to be in an impedance matching state using the control information stored in the storage means. .

  In the antenna matching device of the present invention, in the above configuration, the control means causes the matching so that the value detected by the first detecting means becomes small or the value detected by the second detecting means becomes large. When adaptively controlling the means, the adaptive control processing is completed for any one of the plurality of antenna elements, and other control information corresponding to the control information at that time is read from the storage means, and the read control information is used. A configuration is adopted in which matching means of other antenna elements is adaptively controlled.

  In the antenna matching device according to the present invention, in the above configuration, the control unit includes a transmission evaluation function represented by a predetermined multiplier multiple of a function including the reflected signal detected by the first detection unit, and the second detection unit. A configuration is adopted in which the matching means is adaptively controlled based on a reception evaluation function expressed by a predetermined multiplier multiple of a function including the received signal detected by the means.

  According to these configurations, the first detection means and the second detection means detect whether the impedance is matched or mismatched, and when the impedance is mismatched when the human body is in proximity, such as a call state, a plurality of antennas The impedance matching state is achieved by adaptively controlling the matching means for any of the above, and the impedance matching state is achieved by adaptively controlling the matching means of other antennas using other control information corresponding to the control information at that time. It is possible to shorten the time required until the power loss, and to reduce power loss due to impedance mismatch.

  In the antenna matching device according to the present invention, in the above configuration, the storage means has impedance information matching control information that is in an impedance matching state when the antenna element is close to the human body, and impedance matching when the antenna element is not close to the human body. Control information to be in a state is stored in advance, and the control unit starts the adaptive control process using any of the control information stored in the storage unit as initial control information.

  According to this configuration, depending on whether or not the antenna element is close to the human body, the adaptive control process is started in a state where the deviation of impedance is small by selectively using the initial control information. It is possible to reduce the time required to achieve the alignment state.

  The antenna matching apparatus according to the present invention employs a configuration in which, in the above configuration, an input unit that inputs information on whether or not the antenna element is close to the human body is input to the control unit by the user.

  According to this configuration, the circuit for determining whether or not the antenna element is close to the human body by providing the input means for inputting information on whether or not the antenna element is close to the human body by the user. There is no need to provide it, and a simple circuit configuration can be obtained.

  The antenna matching device of the present invention employs a configuration in which the matching means is a variable capacitor and the control information is a capacitance value of the variable capacitor.

  The antenna matching device according to the present invention employs a configuration in which, in the above configuration, the matching means is a variable capacitance diode, and control information is a control voltage applied to the variable capacitance diode.

  According to these configurations, the matching means can be a variable capacitance capacitor or a variable capacitance diode, and can be brought into an impedance matching state by being controlled by a capacitance value or a control voltage.

  The antenna matching device according to the present invention employs a configuration in which the matching unit includes a plurality of capacitors having different capacities and a switch unit that selectively switches the plurality of capacitors in the above configuration.

  According to this configuration, an impedance matching state can be achieved by selectively switching a plurality of capacitors having different capacitances.

  The antenna matching device of the present invention employs a configuration in which the antenna elements have different resonance frequencies in the above configuration.

  According to this configuration, if the resonance frequency of the antenna element is set to the transmission frequency and the reception frequency, respectively, the time required to establish the impedance matching state can be shortened even when the transmission and reception frequencies are different. , Power loss due to impedance mismatch can be reduced.

  The antenna matching apparatus of the present invention employs a configuration in which, in the above configuration, the control means performs adaptive control processing in a timing slot other than the transmission slot and the reception slot.

  According to this configuration, the influence on the call quality can be reduced and the necessity for performing the adaptive control process at a high speed is low as compared with the case where the adaptive control process is performed in the transmission slot and the reception slot. The processing burden can be reduced.

  As described above, according to the present invention, the impedance adjustment matching means connected to each of the plurality of antenna elements and the information for controlling the matching means so as to be in the impedance matching state are the distance between the antenna elements and the human body. Prepared in advance in the table, and after performing adaptive control processing on any of the plurality of antenna elements, the control information of other matching means corresponding to the control information at that time is read from the table, and the read control information By starting the adaptive control of other matching means using the antenna, the antenna device mounted on the mobile phone or the like can quickly eliminate the impedance mismatch that occurs when the human body is in proximity and reduce the power loss due to the impedance mismatch. Can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing the configuration of the antenna matching apparatus according to Embodiment 1 of the present invention. In this figure, one end of the transmitting antenna element TA1 is connected to a radio housing B1 made of a conductor via a variable capacitor VC1, and a coaxial cable which is an unbalanced feed line via a variable capacitor VC2. Connected to the center conductor of CA1.

  One end of the receiving antenna element RA1 is connected to the radio housing B1 via the variable capacitor VC3, and is connected to the center conductor of the coaxial cable CA2 via the variable capacitor VC4. Note that the ground conductors of the coaxial cables CA1 and CA2 are connected to the radio housing B1. The central conductors of the coaxial cables CA1 and CA2 are connected to the reflected power detection unit 102 and the received power detection unit 103, respectively. Note that the variable capacitors VC1 to VC4 function as matching means.

  The wireless transmission unit 101 performs transmission processing such as encoding, modulation, and D / A conversion on the signal transmitted to the communication partner, and transmits the signal after transmission processing from the transmission antenna element TA1 via the reflected power detection unit 102. It transmits as a radio wave of the credit frequency ft.

  When there is an impedance mismatch in the transmitting antenna element TA1, the reflected power detector 102 detects reflection at the mismatched portion and detects the power of the reflected signal. The detected value is output to the adaptive control unit 105.

  The reception power detection unit 103 detects the power of the signal received by the reception antenna element RA1 and outputs the detected value (detection value) to the adaptive control unit 105.

  The wireless reception unit 104 performs reception processing such as A / D conversion, demodulation, and decoding on the signal received by the reception antenna element RA1.

  The storage unit 106 stores in advance the capacitance value (control information) of the variable capacitor according to the distance between the human body and the antenna element. In addition, initial values of the variable capacitors VC1 to VC4 are stored.

  The adaptive control unit 105 measures the detection value of the reflected power output from the reflected power detection unit 102, reads the capacitance value from the storage unit 106 based on the measurement result, and reflects the reflected power using the read capacitance value as an initial value. The variable capacitors VC1 and VC2 are adaptively controlled so as to be minimized. Further, the detection value of the reception power output from the reception power detection unit 103 is measured, and the variable capacitors VC3 and VC4 are adaptively controlled based on the measurement result.

  Thereby, impedance matching can be achieved for the transmitting antenna element TA1 and the receiving antenna element RA1.

  Here, the storage unit 106 will be described more specifically. FIG. 2 is a diagram illustrating a table stored in the storage unit 106. In this figure, the distance between the human body and the antenna element is dj (1 <= j <= m), and the capacitances of the variable capacitors VC1 and VC2 connected to the transmitting antenna element TA1 are made to correspond to dj, and Cptj , Cstj. Further, the capacitances of the variable capacitors VC3 and VC4 connected to the receiving antenna element RA1 are set to Cprj and Csrj in correspondence with dj. The capacitance values shown here are prepared in advance as impedance matching states at the distance between the corresponding human body and the antenna element, and the capacitance values of the variable capacitors are stored in association with each other.

Next, a processing procedure in the adaptive control unit 105 will be described. FIG. 3 is a flowchart showing a processing procedure of adaptive control section 105 in the embodiment of the present invention. In this figure, in step (hereinafter abbreviated as “ST”) 301, a counter n is initialized and n = 1. In ST302, a transmission initial value is set. Note that yt (n) = {gt (n)} ^q is an evaluation function for transmission, and the following settings are made.
(1) Substitute the initial value yt0 into the evaluation function value yt (0).
(2) The capacitance initial value Cpt0 of the variable capacitor VC1 is substituted into the capacitance value Cpt (0).
(3) Substitute the capacitance initial value Cst0 of the variable capacitor VC2 into the capacitance value Cst (0).
(4) The predetermined capacitance value Cpt1 at n = 1 is substituted into the capacitance value Cpt (1), and the capacitance value of the variable capacitor VC1 is set to Cpt1.
(5) The predetermined capacitance value Cst1 at n = 1 is substituted into the capacitance value Cst (1), and the capacitance value of the variable capacitor VC2 is set to Cst1.

  In ST303, the detection value gt detected by the reflected power detection unit 102 is measured, and the value obtained by the measurement is substituted into gt (1). In ST304, gt (1) obtained in ST303 is substituted into the transmission evaluation function to calculate yt (1).

  In ST305, Δyt and ΔCit (n) (i = p, s) are calculated by the following equations.

Δyt = yt (n−1) −yt (n) (1)
ΔCit (n) = Cit (n−1) −Cit (n) (i = p, s) (2)

In ST306, Cit (n + 1) (i = p, s) is calculated by the following equation using the value obtained in ST305.
Cit (n + 1) = Cit (n) + {Δyt / ΔCit (n)} × δ (i = p, s) (3)
Here, δ is an interval (period) at which the sample (detection value gt) is updated, and is a value determined in advance by the speed at which the value of the transmission evaluation function converges and the residual after convergence.

  In ST307, the variable capacitors VC1 and VC2 are controlled to be Cit (n + 1) calculated in ST306.

  In ST308, the capacity is controlled to Cit (n + 1) in ST307, so that yt (n + 1) is obtained, and yt (n + 1) and yt (n) are compared in size. If yt (n + 1) <yt (n), the process proceeds to ST309, and if yt (n + 1)> = yt (n), the process proceeds to ST310. When the number of repetitions (counter n) is increased according to the calculation method of yt (n + 1), there is n where yt (n + 1)> = yt (n), and at this time, yt (n) is minimized. That is, the reflected signal detection value gt (n) is minimized. Until it is determined that yt (n) is the minimum, the processing from ST305 to ST307 is repeated. When yt (n) is minimized, that is, when the reflected signal detection value gt (n) is minimized, the transmitting antenna element TA1 is in an impedance matching state.

  In ST309, the counter n is incremented, and the process returns to ST305.

  In ST310, the variable capacitors VC1 and VC2 are controlled so as to be Cit (n) that is in the impedance matching state in ST308.

  In ST311, based on the table shown in FIG. 2, Cirj (i = p, s) having a common distance dj corresponding to Cit = Citj = Cit (n) (i = p, s) is read, and the process proceeds to ST312. To do.

Hereinafter, adaptive control is performed for the receiving antenna element RA1. In ST312, the counter n is initialized and n = 1. In ST313, a reception initial value is set. Note that yr (n) = {gr (n)} ^q is a reception evaluation function, and the following settings are made using the values read from the table in ST311.
(1) Substitute the initial value yr0 into the evaluation function yr (0).
(2) Substitute the capacitance initial value Cprj of the variable capacitor VC3 into the capacitance value Cpr (0).
(3) Substitute the capacitance initial value Csrj of the variable capacitor VC4 into the capacitance value Csr (0).
(4) The predetermined capacitance value Cpr1 at n = 1 is substituted into the capacitance value Cpr (1), and the capacitance value of the variable capacitor VC3 is set to Cpr1.
(5) The predetermined capacitance value Csr1 at n = 1 is substituted into the capacitance value Csr (1), and the capacitance value of the variable capacitor VC4 is set to Csr1.

  Thus, by setting Cirj corresponding to Citj in the impedance matching state for the transmitting antenna element TA1 as the initial value of adaptive control of the receiving antenna element RA1, the impedance matching state for the receiving antenna element RA1. It is possible to shorten the time required until

  In ST314, the detection value gr detected by the reception power detection section 103 is measured, and the value obtained by the measurement is substituted into gr (1). In ST315, gr (1) obtained in ST314 is substituted into the reception evaluation function to calculate yr (1).

  In ST316, Δyr and ΔCir (n) (i = p, s) are calculated by the following equations.

Δyr = yr (n−1) −yr (n) (4)
ΔCir (n) = Cir (n−1) −Cir (n) (i = p, s) (5)

In ST317, Cir (n + 1) (i = p, s) is calculated by the following equation using the value obtained in ST316.
Cir (n + 1) = Cir (n) + {Δyr / ΔCir (n)} × δ (i = p, s) (6)

  In ST318, the variable capacitors VC3 and VC4 are controlled so as to be Cir (n + 1) calculated in ST317.

  In ST319, yr (n + 1) is obtained by controlling the capacity to Cir (n + 1) in ST317, and yr (n + 1) and yr (n) are compared in size. If yr (n + 1)> yr (n), the process proceeds to ST320. If yr (n + 1) <= yr (n), the value of the reception evaluation function has converged, and the process proceeds to ST321. Here, according to the calculation method of yr (n + 1), when the number of repetitions (counter n) is increased, there is n where yr (n + 1) <= yr (n). At this time, yr (n) is Maximum. That is, the received signal detection value gr (n) is maximized. Until it is determined that yr (n) is the maximum, the processing from ST316 to ST318 is repeated. When yr (n) is maximized, that is, when the received signal detection value gr (n) is maximized, the receiving antenna element RA1 is in an impedance matching state.

  In ST320, the counter n is incremented, and the process returns to ST316.

  In ST321, the variable capacitors VC3 and VC4 are controlled so as to be Cir (n) that has been in the impedance matching state in ST319. The adaptive control for the receiving antenna element RA1 ends, and the adaptive control process is completed.

  As described above, by performing the processing by the adaptive control unit 105, final capacitors Cpt (n), Cst (n), Cpr (n), and Csr (n) are obtained. At this time, the impedance matching state is obtained. . As a result, when the human body is in proximity, such as in a call state, it is possible to correct impedance deviation, reduce power loss due to mismatch loss, and ensure good call quality.

  In the above description, the variable control capacitor VC3 connected to the receiving antenna element RA1 is performed after the processing procedure of the adaptive control unit 105 is performed by controlling the variable capacitors VC1 and VC2 connected to the transmitting antenna element TA1. In the case of controlling VC4, as shown in ST401 to ST411 of FIG. 4, after controlling the variable capacitors VC3 and VC4 connected to the receiving antenna element RA1, the transmission is performed in ST412 to ST421. Control of the variable capacitors VC1 and VC2 connected to the trusted antenna element TA1 may be performed. That is, the adaptive control unit 105 can start the adaptive control process regardless of reception or transmission.

  FIG. 5 is a schematic diagram showing transmission / reception timing slots. In this figure, the timing slots are configured in the order of an idle slot 501, a reception slot 502, and a transmission slot 503. It goes without saying that the adaptive control process described above is performed in the reception slot 502 and the transmission slot 503, but may be performed in the idle slot 501. The idle slot 501 is a slot used for transmission / reception of control signals. When adaptive control processing is performed in the idle slot 501, there is no need to ensure high call quality unlike the transmission / reception slot, so adaptive control processing is performed at high speed. It does not have to be. For this reason, it is possible to reduce the processing load required for the calculation.

  As described above, according to the present embodiment, a variable capacitor for impedance adjustment is connected to each of the transmitting antenna element and the receiving antenna element, and the capacitance value of each variable capacitor that is in an impedance matching state is determined between the antenna element and the human body. Prepared in advance in a table corresponding to the distance between and the adaptive control processing for either the transmitting antenna element or the receiving antenna element is completed, and the other capacitance value corresponding to the capacitance value at that time is read from the table, By performing adaptive control processing for other antenna elements with the read value as the initial value, even if the distance between the antenna element and the human body fluctuates and an impedance shift occurs, an impedance matching state can be achieved in a short time. Power loss due to impedance mismatch, ensuring good call quality. It can be.

(Embodiment 2)
In the first embodiment, the case where the impedance matching is realized by controlling the capacitance value of the variable capacitor has been described. However, in this embodiment, the impedance matching is realized by controlling the voltage applied to the variable capacitance diode. Will be described.

  FIG. 6 is a block diagram showing the configuration of the antenna matching apparatus according to Embodiment 2 of the present invention. However, the parts in FIG. 6 that are the same as those in FIG. 1 are denoted by the same reference numerals as those in FIG.

  One end of the transmitting antenna element TA1 is connected to the cathode of the variable capacitance diode VD1 at the connection point P1, and the anode of the variable capacitance diode VD1 is connected to the wireless device case via the high frequency blocking inductor L1 connected to the connection point P31. Connected to B1.

  One end of the transmitting antenna element TA1 is connected to the high frequency blocking inductor L2 at the connection point P1, and the high frequency blocking inductor L2 is connected to the output terminal of the control voltage Vpt of the adaptive control unit 603.

  Further, one end of the transmitting antenna element TA1 is connected to the DC voltage blocking capacitor C1 at the connection point P1, and the DC voltage blocking capacitor C1 is connected to the cathode of the variable capacitance diode VD2 and the high frequency blocking inductor L3 at the connection point P11. Is connected to the output terminal of the control voltage Vst of the adaptive control unit 603.

  The anode of the variable capacitance diode VD2 is connected to the central conductor of the coaxial cable CA1 via the DC voltage blocking capacitor C2 at the connection point P12, and is connected to the radio equipment case B1 via the high frequency blocking inductor L4. Yes.

  One end of the receiving antenna element RA1 is connected to the cathode of the variable capacitance diode VD3 at the connection point P2, and the anode of the variable capacitance diode VD3 is connected to the wireless device case via the high frequency blocking inductor L5 connected to the connection point P32. Connected to B1.

  One end of the receiving antenna element RA1 is connected to the high frequency blocking inductor L6 at the connection point P2, and the high frequency blocking inductor L6 is connected to the output terminal of the control voltage Vpr of the adaptive control unit 603.

  Further, one end of the receiving antenna element RA1 is connected to the DC voltage blocking capacitor C3 at the connection point P2, and the DC voltage blocking capacitor C3 is connected to the cathode of the variable capacitance diode VD4 and the high frequency blocking inductor L7 at the connection point P21. To the output terminal of the control voltage Vsr of the adaptive control unit 603. Here, the control voltage corresponds to the control information.

  The anode of the variable capacitance diode VD4 is connected to the central conductor of the coaxial cable CA2 via the DC voltage blocking capacitor C4 at the connection point P22, and is connected to the radio equipment case B1 via the high frequency blocking inductor L8. Yes.

  The storage unit 601 enters the impedance matching state when the antenna element is not close to the human body and the control voltage (Vpt, Vst, Vpr, Vsr) that is in the impedance matching state when the antenna element is close to the human body. Control voltages (Vpt, Vst, Vpr, Vsr) are stored as initial values. Further, a table in which the capacitance value shown in FIG. 2 is changed to the control voltage is stored.

  The input unit 602 includes a switch, a button, and the like, and notifies the adaptive control unit 603 whether the user is in proximity to the human body or not in proximity to the human body by switching the switch. Thereby, it is not necessary to provide a circuit for determining whether or not the antenna element is close to the human body, and a simple circuit configuration can be obtained.

  The adaptive control unit 603 reads the control voltage stored in the storage unit 601 according to the content notified from the input unit 602, and uses the read control voltage as an initial value for adaptive control.

  As a result, the difference between the control voltage when the impedance matching state is achieved by adaptive control and the initial value is reduced, and the time required until the impedance matching state is reached can be shortened. For this reason, stable call quality can be ensured.

  Note that the processing in the adaptive control unit 603 only changes the capacitance value described in the first embodiment to the control voltage, and the other processing is the same as that in the first embodiment, and thus detailed description thereof is omitted.

  As described above, according to the present embodiment, the control voltage that is in the impedance matching state when the antenna element is close to the human body, and the control voltage that is in the impedance matching state when the antenna element is not close to the human body, Are prepared in advance as initial values, the initial value is selected according to whether or not the antenna element is close to the human body, and adaptive control processing is performed using the selected initial value until the impedance matching state is achieved. Can be shortened and stable call quality can be ensured.

(Embodiment 3)
FIG. 7 is a block diagram showing a configuration of an antenna matching apparatus according to Embodiment 3 of the present invention. However, the parts in FIG. 7 that are the same as those in FIG. 1 are given the same reference numerals as those in FIG.

  One end of the transmitting antenna element TA1a is connected to a radio housing B1 made of a conductor via a variable capacitor VC1a, and a central conductor of a coaxial cable CA1a that is an unbalanced feed line via a variable capacitor VC2a. It is connected to the. Note that the ground conductor of the coaxial cable CA1a is connected to the radio housing B1. The central conductor of the coaxial cable CA1a is connected to the reflected power detection unit 102a.

  One end of the receiving antenna element RA1a is connected to a radio housing B1 made of a conductor via a variable capacitor VC3a, and a central conductor of a coaxial cable CA2a that is an unbalanced feed line via a variable capacitor VC4a. It is connected to the. Note that the ground conductor of the coaxial cable CA2a is connected to the radio housing B1. The central conductor of the coaxial cable CA2a is connected to the received power detection unit 103a.

  The wireless transmission unit 101a has the same configuration as the wireless transmission unit 101, the reflected power detection unit 102a has the same configuration as the reflected power detection unit 102, the reception power detection unit 103a has a reception power detection unit 103, and the reception radio unit 104a has a reception radio unit. 104 has the same configuration. Note that the value detected by the reflected power detection unit 102a is denoted by gta, and the value detected by the reception power detection unit 103a is denoted by gra. The frequency band used by the combination of the transmitting antenna element TA1 and the receiving antenna element RA1 is different from the frequency band used by the combination of the transmitting antenna element TA1a and the receiving antenna element RA1a.

  The storage unit 701 has a capacitance value of the variable capacitor connected to the transmitting antenna elements TA1 and TA1a and a capacitance value of the variable capacitor connected to the receiving antenna elements RA1 and RA1a. It is stored in association with the distance. In addition, the initial capacitance value of each variable capacitor is stored.

  The adaptive control unit 702 measures the detection values gt and gta detected by the reflected power detection units 102 and 102a, reads the capacitance value from the storage unit 701 based on the measurement result, and reflects the read capacitance value as an initial value. The variable capacitor is adaptively controlled so that the power is minimized. In addition, the detection values gr and gra detected by the reception power detection units 103 and 103a are measured, the capacity value is read from the storage unit 701 based on the measurement result, and the reception power is maximized with the read value as an initial value. Thus, the variable capacitor is adaptively controlled.

  As described above, according to the present embodiment, when a plurality of sets of transmitting antenna elements and receiving antenna elements are provided and each set corresponds to a different frequency, the distance between the antenna element and the human body varies, Even when an impedance deviation occurs, the impedance matching state can be achieved in a short time, so that power loss due to impedance mismatching can be reduced and good call quality can be ensured.

(Other embodiments)
FIG. 8 is a block diagram showing an antenna matching apparatus according to another embodiment of the present invention. However, the parts in FIG. 8 common to FIG. 1 are denoted by the same reference numerals as those in FIG. FIG. 8 differs from FIG. 1 in that the variable capacitor is changed to a capacitance switching unit including a plurality of capacitors and a changeover switch.

  The capacitance switching unit 801 serving as a matching unit includes a plurality of capacitors having different capacitance values Cpt1 to CptN, and switches connected capacitors by controlling the changeover switch. The same applies to the capacity switching units 802 to 804.

  The present embodiment can be applied to the above-described first to third embodiments, and the capacity switching units 801 to 804 are controlled by the adaptive control unit.

  In each of the embodiments described above, the antenna element may be a helical antenna or a whip antenna. Each antenna element may have a different resonance frequency.

  In each of the embodiments described above, the reflected power detection unit detects the power of the reflected signal. However, the present invention is not limited to this, and any one of the reflected signal, the reflection coefficient, and the voltage standing wave ratio is detected. It may be.

  In each of the above-described embodiments, the adaptive control unit adaptively controls the variable capacitance element so that the value detected by the reflected power detection unit becomes smaller or the value detected by the received power detection unit becomes larger. In this case, the adaptive control process is completed for any one of the plurality of antenna elements, other control information corresponding to the control information at that time is read from the storage unit, and the read control information is used to Although it has been described that the variable capacitance element is adaptively controlled, the present invention is not limited to this, and broadly includes adaptive control of the variable capacitance element so as to be in an impedance matching state using control information stored in the storage unit. It is a waste.

  The antenna matching device according to the present invention has an effect that an antenna device mounted on a mobile phone or the like eliminates impedance mismatch occurring in the vicinity of a human body in a short time and reduces power loss due to impedance mismatch. It can be applied to wireless communication devices such as mobile phones.

The block diagram which shows the structure of the antenna matching apparatus which concerns on Embodiment 1 of this invention. The figure which shows the table memorize | stored in the memory | storage part. The flowchart which shows the process sequence of the adaptive control part in embodiment of this invention The flowchart which shows the process sequence of the adaptive control part in embodiment of this invention Schematic diagram showing the transmission / reception timing slot The block diagram which shows the structure of the antenna matching apparatus which concerns on Embodiment 2 of this invention. The block diagram which shows the structure of the antenna matching apparatus which concerns on Embodiment 3 of this invention. The block diagram which shows the antenna matching apparatus which concerns on other embodiment of this invention. The figure which shows the structure of the conventional mobile telephone The figure which shows an example at the time of the human body proximity | contact of a mobile telephone

Explanation of symbols

101, 101a Radio transmission unit 102, 102a Reflected power detection unit 103, 103a Reception power detection unit 104, 104a Radio reception unit 105, 603, 702 Adaptive control unit 106, 601, 701 Storage unit 501 Idle slot 502 Reception slot 503 Transmission slot 602 Input unit 801 to 804 Capacity switching unit

Claims (10)

A plurality of antenna elements;
A matching means connected to each of the antenna elements for adjusting impedance;
First detection means for detecting one of a signal reflected when power is supplied to the antenna element, a reflection coefficient, and a voltage standing wave ratio;
Second detection means for detecting a signal received by the antenna element;
Storage means for storing the control information of the matching means in association with the distance between the human body and the antenna element;
Control means for adaptively controlling the matching means so as to be in an impedance matching state using the control information stored in the storage means;
An antenna matching apparatus comprising:   When the control means adaptively controls the matching means so that the value detected by the first detection means becomes smaller or the value detected by the second detection means becomes larger, the plurality of antenna elements Adaptive control processing is completed for any of the above, and other control information corresponding to the control information at that time is read from the storage means, and the matching means of other antenna elements is adaptively controlled using the read control information The antenna matching device according to claim 1.   The control means includes a transmission evaluation function expressed by a predetermined multiplier multiple of a function including the reflected signal detected by the first detection means, and a function predetermined including the reception signal detected by the second detection means. The antenna matching apparatus according to claim 1 or 2, wherein the matching unit is adaptively controlled based on a reception evaluation function expressed by a multiplier multiple of. The storage means stores in advance control information that is in an impedance matching state when the antenna element is close to the human body, and control information that is in an impedance matching state when the antenna element is not close to the human body,
4. The antenna matching apparatus according to claim 1, wherein the control unit starts adaptive control processing using any control information stored in the storage unit as initial control information. 5.   5. The antenna matching apparatus according to claim 4, further comprising an input unit that inputs information on whether or not the antenna element is close to a human body to the control unit by a user.   6. The antenna matching apparatus according to claim 1, wherein the matching unit is a variable capacitor, and the control information is a capacitance value of the variable capacitor.   6. The antenna matching apparatus according to claim 1, wherein the matching means is a variable capacitance diode, and control information is a control voltage applied to the variable capacitance diode.   6. The antenna matching apparatus according to claim 1, wherein the matching unit includes a plurality of capacitors having different capacities and a switch unit that selectively switches the plurality of capacitors. .   9. The antenna matching apparatus according to claim 1, wherein the antenna elements have different resonance frequencies.   10. The antenna matching apparatus according to claim 1, wherein the control means performs adaptive control processing in a timing slot other than a transmission slot and a reception slot.

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